1. Field of the Invention
This invention relates to compositions and methods for providing chicken with sustained protection from infection with Salmonella enteritidis. More specifically, this invention relates to biodegradable and biocompatible polymeric microspheres encapsulating S. enteritidis which can be administered to chickens to protect them from S. enteritidis infections.
2. Background Art
Salmonella enteritidis, an agent which causes salmonellosis in poultry, can be transmitted vertically from laying hens to eggs. Consumption of eggs or meat contaminated with the organism can lead to food poisoning in humans. This is a worldwide problem in public health; in the U.S. alone, more than a million cases of salmonellosis are reported annually. Outbreaks in the elderly and in young children can be especially dangerous, resulting in severe gastroenteritis and possibly fatal septicemia.
In view of the large number of cases of Salmonella enteritidis cases reported each year, there is an obvious need for a reliable method for controlling the spread of Salmonella intestinal pathogens in poultry and for preventing the transmission of the pathogens into their eggs. Avirulent and killed injectable S. enteritidis vaccines have been developed and are useful. These vaccination processes, however, are known to cause a large amount of stress to the chicken as multiple vaccinations are required.
There thus is a significant need for a method by which poultry can be immunized against S. enteritidis in a simple, single dose, efficient, and cost-effective manner.